1. Field of the Invention
The present invention relates to a method of designing a rotary thermal actuator and a rotary thermal actuator, and more particularly, to a rotary thermal actuator and a method of designing a rotary thermal actuator, which has superior rotation performance and used in a micro-electromechanical system (MEMS) structure, through topology optimization design using an element connectivity parameterization method.
2. Description of the Related Art
Various methods of driving micro-electromechanical system (MEMS) apparatuses, such as a driving method using electrostatic force and a driving method using thermal expansion, have been developed. In particular, comb drive actuators using electrostatic force have a short response time due to the properties of electrostatic force and are easy to design. Therefore, the comb drive actuators are widely used to make horizontal, vertical, and rotational motions.
However, the force of the comb drive actuators using electrostatic force is relatively weak compared with the size thereof. Therefore, a larger actuator and a higher driving voltage are required in order to obtain greater force. In particular, MEMS apparatuses for optical communication require very large comb drive actuators that can drive relatively large and heavy mirrors.
On the other hand, thermal actuators using thermal expansion caused by electric energy are easy to manufacture and have relatively stronger force. Therefore, the thermal actuators can replace the comb drive actuators using electrostatic force.
However, while it is possible to make linear motions using the thermal actuators, it is difficult to make rotational motions. Accordingly, topology optimization researches of various forms for thermal actuators have been studied. However, the major portion of them is for simple to-and-fro motions, and driving, such as rotational motions, has not been specifically designed.